THE ROYAL ARTILLERY INSTITUTION. 
187 
tlie left . That all were not to the left at 5° and 10° arose most probably 
from the unsteadiness of some shot and the turning over of others during 
flight; for the grazes of the shot which deflected to the right showed that 
the axis of the shot was considerably inclined to the line of the range. The 
unsteadiness during flight of the special shot at 5° and 10°, which might 
have been inferred from the inaccuracy of the practice, was noticed both at 
the battery and on the range. 
Now as the special shot were unsteady when fired even at 5°, in con¬ 
sequence of the gun not giving a sufficiently high velocity of rotation for 
flat-headed projectiles, I suggested that the remaining special shot should be 
fired at 2°, 3°, and 4°; this was done on the 9th and 18th April, 1864, and 
very decisive results were obtained. The following were the mean deflections 
obtained on the 9 th April, Table Y.:— 
2° 3° 
yds. yds. 
Service shot. . *2 left *2 left 
Special shot (centre of gravity towards point)... 2*8 left 2 - 3 left 
The mean deflections on 18 th April, Table YI., were, 
2° 3° 
yds. yds. 
Service shot.. 1*6 left 1*4 right 
Special shot (centre of gravity towards base) ... 3*4 left 7*8 left 
4° 
yds. 
line. 
3*46 left. 
4° 
yds. 
T9 right. 
8-46 left. 
On both days the wind blew from right to left and will account for some 
of the service shot having a slight deflection to the left; every one who has 
seen much practice is aware that the right deflection of the service shot is 
hardly sensible at low angles of elevation, and that a little wind blowing 
from right to left is sufficient to counteract it. 
I have purposely omitted to notice No. 1 round with service shot. Table 
YI., for the deflection 8 yds. left, is evidently a very wild one, there being no 
such eccentric graze (at 2°) recorded in any of the practice returns given in 
Tables III., IY., Y. and YI., or in numerous other practice returns I have 
purposely consulted. 
On the 9th April, Table Y., it was noticed that at 2° the special shot 
were steady during flight; at 3° they were unsteady near the end of the 
range; and at 4° they were unsteady for some distance before grazing. As 
might have been supposed the left deflections of the special shot with 
preponderance behind were greater than those of the special shot with 
preponderance in front. 
The results of the experiments shown in the preceding Tables are, I 
conceive, sufficient to establish the following facts :— 
(1) That elongated projectiles with rounded or pointed heads deflect to 
the right at ordinary ranges when fired with right-handed rotation. 
(2) That similar projectiles fired with left-handed rotation deflect to the 
left . 
(3) That the derivation of cylindrical or flat-headed projectiles is in the 
opposite direction to that of projectiles with rounded or pointed heads fired 
